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View Full Version : Bug in P-47 Gun Recoil causes Plane to veer right



XyZspineZyX
09-06-2003, 08:19 PM
Salute All

I have been doing some testing on the P-47's and other aircraft's guns to see how they compare for scatter, recoil etc.

I was surprised to see that the P-47, uniquely among aircraft with wing mounted guns, has a pronounced tendency to swing to the right when all the guns are fired. This tendency occurs whether the aircraft has full fuel and ammunition load or not.

Considering the P-47 is the heaviest fighter in the Sim, and thus would have the greatest inertia for its gun recoilto overcome, and thus should be the most stable, it seems incorrect that it should be affected by recoil in this way.

You can do this test yourself quite easily.

Simply load up any dogfight server, make sure you have External Views enabled, select a P-47 with full fuel and ammunition and start on the field. Go to External view and zoom back to show the entire taxi way area. (hold down left mouse button and move mouse to zoom in or out)

Then fire both sets of guns simultaneously. You will see the P-47 begin to back up. But unlike other aircraft which are also pushed back by the recoil of their guns, the P-47 is not pushed straight back. It begins to describe a circle, and in fact will do a complete circle in the dispersal area of the field if you have loaded unlimited ammunition.

Try the same test with a 190A8 which has a larger set of guns in the wings, which have heavier recoils and it will roll backwards in a straight liine.

Same with all the fighters I tested with wing mounted guns, including the P-40 with its three .50 calibre guns.

I have sent a letter to Oleg along with a .ntrk to request this bug be fixed, and have every confidence it will be.


Cheers RAF74 Buzzsaw



Message Edited on 09/06/0307:19PM by RAF74BuzzsawXO

XyZspineZyX
09-06-2003, 08:19 PM
Salute All

I have been doing some testing on the P-47's and other aircraft's guns to see how they compare for scatter, recoil etc.

I was surprised to see that the P-47, uniquely among aircraft with wing mounted guns, has a pronounced tendency to swing to the right when all the guns are fired. This tendency occurs whether the aircraft has full fuel and ammunition load or not.

Considering the P-47 is the heaviest fighter in the Sim, and thus would have the greatest inertia for its gun recoilto overcome, and thus should be the most stable, it seems incorrect that it should be affected by recoil in this way.

You can do this test yourself quite easily.

Simply load up any dogfight server, make sure you have External Views enabled, select a P-47 with full fuel and ammunition and start on the field. Go to External view and zoom back to show the entire taxi way area. (hold down left mouse button and move mouse to zoom in or out)

Then fire both sets of guns simultaneously. You will see the P-47 begin to back up. But unlike other aircraft which are also pushed back by the recoil of their guns, the P-47 is not pushed straight back. It begins to describe a circle, and in fact will do a complete circle in the dispersal area of the field if you have loaded unlimited ammunition.

Try the same test with a 190A8 which has a larger set of guns in the wings, which have heavier recoils and it will roll backwards in a straight liine.

Same with all the fighters I tested with wing mounted guns, including the P-40 with its three .50 calibre guns.

I have sent a letter to Oleg along with a .ntrk to request this bug be fixed, and have every confidence it will be.


Cheers RAF74 Buzzsaw



Message Edited on 09/06/0307:19PM by RAF74BuzzsawXO

XyZspineZyX
09-06-2003, 08:21 PM
how do you know it didnt do that in real life

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XyZspineZyX
09-06-2003, 08:33 PM
Salute Bobsqueek

Oh darn Bobsqueek, I forgot.

All American designers deliberated built gun designs into their Fighters that would cause pilots to miss their target.

Only Germans were clever enough to put guns in their planes and then align them so they could hit.

How silly of me not to remember and how brilliant of you to point out my foolishness... /i/smilies/16x16_smiley-wink.gif






Message Edited on 09/06/0307:34PM by RAF74BuzzsawXO

XyZspineZyX
09-06-2003, 08:44 PM
I noticed the Lagg 3 `43 does this too. But I assumed it to be normal. I noticed no note from RAF74BuzzsawXO about this.

What is it with you, m8? Aren`t you satisfied? This isn`t about getting an accurate P-47, it`s really about the P-47 according to RAF74BuzzsawXO.

If you were truly trying to be helpful you`d test EVERY SINGLE aircraft in FB, compare them, test them in an UNBIASED manner, then report.

As far as you`re concerned Damn the rest of the aircraft in the world of FB, just as long as YOUR VERSION of the P-47 flies according to your point of view.

Just go out there and ENJOY the game/simulation. Don`t argue, take a walk, go on your PC and just play the sim which was created from the idea of one man who loved the IL2 and WWII planes generally. Stop being so fixated!





"Tis better to work towards an Impossible Good, rather than a Possible Evil."

SeaFireLIV.

XyZspineZyX
09-06-2003, 08:47 PM
Buzzsaw - the P47 tends to pull right on take off,
doesn't it? Perhaps what is being modelled is a
slight reduction in airspeed due to the guns being
fired (I know it has been debated as to whether
there should be any reduction!) and that is somehow
allowing engine torque to pull the plane right? It
is the best speculative theory I can come up with
at the moment!

XyZspineZyX
09-06-2003, 08:58 PM
Salute Aaron

All planes with propellors which rotate are pulled either right or left by that torque. None of the other planes in the Sim seem to be affected by this.

In the case of the P-47, having lower powerloading than other aircraft such as the 109's or 190's, it should be less affected by torque.


RAF74 Buzzsaw

XyZspineZyX
09-06-2003, 09:03 PM
Salute Seafire

Firstly: Not sure what caused your outburst, but guess what?

I don't need permission from you to do anything.... /i/smilies/16x16_smiley-wink.gif

Secondly, I did test every aircraft in the Sim with Wing mounted guns. The P-47 was the only one affected this way that I found.

If you have a problem with the LaGG-3, which has cowling and nose mounted guns, then report it. In the case of the LaGG, there could be a reason. Ie. it has an asymetrical mounting of weapons, ie. 1 12.7mm and 1 7.62mm in the cowling, ie. unbalanced. That could cause it to veer.

Thirdly, I fly FORGOTTEN BATTLES regularly with my Squadron as well as on other servers. If you would like join us, we should be on this evening. (U.S. EST)

I would be happy to demonstrate my regular practice by turning your aircraft into scrap metal repeatedly. /i/smilies/16x16_smiley-happy.gif


RAF74 Buzzsaw



Message Edited on 09/06/0308:04PM by RAF74BuzzsawXO

XyZspineZyX
09-06-2003, 10:42 PM
thats right and the problem appears when you are in a dogfight with a speed lest than 300 KM/H them you see that efect on the plane. Of couse there must be a recoil but not an tendecy to move to one site...


Maybe this is the case why the plane is not so efective with the guns by some people

XyZspineZyX
09-06-2003, 10:57 PM
There are to many aircraft, and to much to know about them for any one person to be able to test all of them completely; people must specialise by necessety. Buzz has chosen to specialise in a single aircraft. Others have chosen to specialise in a single aspect of flight. However, noone can learn every thing about every aircraft that is flown in Forgotten Battles. I suspect even the people employeed by 1:C Maddox Games are relatively specialised in their fields.

As for the subject of the LaGG-3 1943 model having a right swing when firing, it probably ought to be looked into, but it does have an asymetrical fire, so it seems reasonable that it would have some swing.

The P-47 on the other hand, has a symetrical weapons distrebution, so it would seam reasonable that it would not have a pronounced swing in any one direction.

Harry Voyager

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XyZspineZyX
09-06-2003, 11:00 PM
My P-47 veers vertically, not to the right...

1 Judge not, that ye be not judged.
2 For with what judgment ye judge, ye
shall be judged: and with what
measure ye mete, it shall be
measured to you again.

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XyZspineZyX
09-06-2003, 11:50 PM
RAF74BuzzsawXO wrote:
- In the case of the P-47, having lower powerloading
- than other aircraft such as the 109's or 190's, it
- should be less affected by torque.

good point.

It was just a theory.

It could just be a bug, of course.



Message Edited on 09/06/0310:53PM by AaronGT

XyZspineZyX
09-06-2003, 11:55 PM
I notiecd that too, very odd. It also does it with the engine off, so nothing to do with torque.

http://www.smiliedb.de/s/sdb06894.gif http://www.smiliedb.de/s/sdb57471.gif http://www.smiliedb.de/s/sdb11726.gif http://www.smiliedb.de/s/sdb75733.gif http://www.smiliedb.de/s/sdb80477.gif http://www.smiliedb.de/s/sdb64472.gif http://www.smiliedb.de/s/sdb59442.gif http://www.smiliedb.de/s/sdb80347.gif http://www.smiliedb.de/s/sdb73057.gif http://www.smiliedb.de/s/sdb48642.gif http://www.smiliedb.de/s/sdb24962.gif http://www.smiliedb.de/s/sdb72600.gif http://www.smiliedb.de/s/sdb72327.gif http://www.smiliedb.de/s/sdb10373.gif http://www.smiliedb.de/s/sdb70750.gif

XyZspineZyX
09-07-2003, 12:00 AM
It does it in the P-40 too, but it goes in the other direction (nose yaws left).

http://www.smiliedb.de/s/sdb06894.gif http://www.smiliedb.de/s/sdb57471.gif http://www.smiliedb.de/s/sdb11726.gif http://www.smiliedb.de/s/sdb75733.gif http://www.smiliedb.de/s/sdb80477.gif http://www.smiliedb.de/s/sdb64472.gif http://www.smiliedb.de/s/sdb59442.gif http://www.smiliedb.de/s/sdb80347.gif http://www.smiliedb.de/s/sdb73057.gif http://www.smiliedb.de/s/sdb48642.gif http://www.smiliedb.de/s/sdb24962.gif http://www.smiliedb.de/s/sdb72600.gif http://www.smiliedb.de/s/sdb72327.gif http://www.smiliedb.de/s/sdb10373.gif http://www.smiliedb.de/s/sdb70750.gif

XyZspineZyX
09-07-2003, 04:36 AM
The Hurricane yaws when the guns are fired also, but I have no problem with it.

XyZspineZyX
09-07-2003, 05:24 AM
It may yaw on the ground but not in the air. A trimmed, fully loaded and armed P-47 I flew in QMB laid down a straight line of fire along a railway line with no swing requiring rudder correction.

XyZspineZyX
09-07-2003, 07:13 AM
Yep she deffinetly veers to the right when fired. Something is deffinetly wrong. Its almost like some of the guns on the right wing are showing the firing animation and sound, but arn't actually shooting thus producing the yaw you see when you have jammed guns on one side of the plane.

Its a obvious bug, it makes no sense to me at all why a plane with the same amount of guns on both sides would yaw one way with the engine turned off.

Message Edited on 09/07/0306:13AM by Zacast

XyZspineZyX
09-07-2003, 07:19 AM
Glad to know it wasn't just me. It also does this on my machine. I do believe it is a bug.

XyZspineZyX
09-07-2003, 11:22 AM
No I don`t have a problem with the Lagg3. Neither do I have a problem with the P-47. And of course it`s a sort of democracy so you have the right to say what you wish, sir.

It`s the constant over-analysis of one plane. It comes across to me pointless to force one plane to be perfected when none of us are sure about all the others.

I`ve only flown the P-47 a few times, partly cos I`ve been put off by this constant analysis of it. I`ll fly the P40, P39 quite happily though. But all these planes seem to fly pretty well to me. Yes, I have no documents, no proof, nothing. I simply approach it from the fresh eyes of a young (ish) fighter pilot who has a job to do.

Also the biggest problem (Rollrate) has apparently been fixed. It`s seeing that almost immediatly that this is done we have a complaint about it veering sideways now. It could be the stick, your settings, whatever, but no, straight here to post the P-47 needs further changes.

The bullet thing I find also improbable. No matter how good an engine is I cannot believe that there isn`t a CHANCE one bullet could put its engine of action. Even modern day aircraft have a chance to fail if hit by one bullet in the right place at the right time. But I digress...

anyway...

In my opinion it`s no good getting one plane to fly exactly perfectly to what documents/proof you have without knowing (to the same extent) the capabilities of every other plane and correcting likewise. Because what do we get? K4 major bug?

A P-47 that`s (according to you) perfect, flying among other planes that aren`t. Then you really still don`t have accuracy at all, do you?

But you seem to imply that you`ve tested every plane. I find that hard to believe, if so well done and my apologies.

Oh, and I may take you up on that offer. I am under a different name, but I`ll reveal it at the time. /i/smilies/16x16_smiley-happy.gif

p.s. Damn! This is long-winded! I`m getting like you! /i/smilies/16x16_smiley-wink.gif No more arguing from me!!



"Tis better to work towards an Impossible Good, rather than a Possible Evil."

SeaFireLIV.

XyZspineZyX
09-07-2003, 04:10 PM
SeaFireLIV wrote:
-
- It`s the constant over-analysis of one plane. It
- comes across to me pointless to force one plane to
- be perfected when none of us are sure about all the
- others.
-

Did you, by any chance, miss the reems of pages generated on both the 109 and the 190? The 190 folks are currently having a very long debate reguarding 3-5 degrees of downward visibility, to the point that the moderators declared that everything had to be confined to one thread and locked all the rest of them.

The only reason we've had a recent slacking off on the 109 threads is because most of the VVS planes got very nerfed in the 1.1b patch. Go poke around in here three or four months ago, and you'll find that we've been relatively restrained in our nitpicking.

Now consider that the P-47 was numerically the more importaint USAAF fighter of the war, and the only modern fighter we currently have (The late model P-39's are more Russian than USAAF, and saw service only in the Eastern Front), and you may understand why we are so nit-picky about it.

Consider what the LW would be like if the only LW fighter in the game was the FW-190A-8. Every comment they made would be pertaining to the Fw-190A-8, and they would seem to be incredibly nit-picky about that plane.

Consider additionally, this is the English speaking forum. A very large percentage of the users here are going to be American or British. There aren't many British aircraft in the game, only the Hurricain, and it wasn't really a major player late in the war, so they don't have one of their aircraft to talk about yet. However, for the Americans, both North and South, the P-47 was the plane they went to war in. It is a part of our cultural history, the same was the Spitfire is in Britain, and the Il-2 is in Russia. Sooner or later we'll see a greater variety of US aircraft imported into Il-2, and the whining will diversify quite a bit, but until then, the P-47 is really the only US plane we have to talk about.

Harry Voyager

http://groups.msn.com/_Secure/0YQDLAswcqmIpvWP9dLzZVayPXOmo6IJ16aURujNfs4dDETH84 Q6eIkCbWQemjqF6O8ZfvzlsvUUauJyy9GYnKM6!o3fu!kBnWVh BgMt3q2T3BUQ8yjBBqECLxFaqXVV5U2kWiSIlq1s6VoaVvRqBy Q/Avatar%202%20500x500%20[final).jpg?dc=4675409848259594077

XyZspineZyX
09-07-2003, 05:38 PM
buzzsaw...has this been reported as a bug???

XyZspineZyX
09-07-2003, 09:37 PM
buzzsaw - I tested the P47 today (only got chance
to play around in the D-27, engine on and off).
No tendency to veer in the 1.1 final (rejected) patch.

XyZspineZyX
09-08-2003, 09:53 AM
AaronGT wrote:
- buzzsaw - I tested the P47 today (only got chance
- to play around in the D-27, engine on and off).
- No tendency to veer in the 1.1 final (rejected)
- patch.
-

Beg to differ AaronGT - using 1.1F with D27 on ground, engine off; inboard guns yaw the nose to the right (consistent and significant movement), outboard guns make it wiggle a little and seem to have more of a movement to the left (though not especially pronounced). All guns together pushes the plane backwards as well as swinging the nose to the right.

I notice the aim spoiling movement in all 3 FB versions of the 47 (high speed reduces the effect). Now if the guns had a bit more punch I wouldn't mind the trade off /i/smilies/16x16_robot-happy.gif - but at present it is very difficult to keep a gun solution for the 1-3 seconds required to get the kill.

Salute

Athos





"When first under fire and you're wishful to duck, don't look nor take heed at the man that is struck, be thankful you're living, and trust to your luck, and face to your front like a soldier"
ex. Rudyard Kipling

XyZspineZyX
09-08-2003, 10:01 AM
Did you lock your tail wheels?



-----------
Due to pressure from the moderators, the sig returns to..

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XyZspineZyX
09-08-2003, 10:19 AM
Maybe it's got something to do with side-slip?

We always assume our planes would be flying totally straight, but there's always some amount of side-slip to be accounted and corrected for.

Normally the effect of side-slip is usually more visible in planes with center-line armament, where narrowly spaced lins of tracers pinpoint your bullet trajectory(well, not exactly same as normal rounds, but in broader aspect..) and clearly indicates you that while in a side slip, the bullets always seem to veer into a certain direction.

Since .50s in FB don't have largely visible smoke trails, an the dispersion usually enables one to land hits even if we spray in a general direction, maybe the 'bullets veering' becomes more visible when somebody takes a careful look to confirm its trajectory.

Hmm.. I think I'd better test it myself in a properly rudder trimmed P-47.. but the last time I shot something with the P-47, like Aaron said, the recoil shakes the sight around, but it didn't seem to have a specific direction of movement..



-----------
Due to pressure from the moderators, the sig returns to..

"It's the machine, not the man." - Materialist, and proud of it!

XyZspineZyX
09-08-2003, 01:18 PM
Athosd wrote:
- Beg to differ AaronGT - using 1.1F with D27 on
- ground, engine off; inboard guns yaw the nose to the
- right (consistent and significant movement),

I did it in the air. No movement with engine on or
off thatI could see. There is recoil, but no consistent
yaw that I could discern. I can do a track if you like.

I didn't try it on the ground.

XyZspineZyX
09-08-2003, 01:21 PM
YE I noticed it ages ago too.. P-47 should be stable gun platform.. at the moment it is not.

____________________________________



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XyZspineZyX
09-08-2003, 01:30 PM
Vipez- wrote:
- YE I noticed it ages ago too.. P-47 should be stable
- gun platform.. at the moment it is not.

The P47 as a whole shouldn't be buffeted too much
by the gun recoil comapared to other planes with
similar amounts of recoil from the guns. As to whether
there is significant wing flex from 8 .50s leading
to extra scatter, that's another matter. (A criticism
of some 4 20mm cannon armed RAF planes was the recoil
causing scatter, although I am not sure it would
have bothered a thick-winged plane such as the Typhoon
overly much, but it might have been an issue for the
4 cannon Spitfires?)

XyZspineZyX
09-08-2003, 08:09 PM
RAF74BuzzsawXO wrote:
- Salute Seafire
-
- Firstly: Not sure what caused your outburst, but
- guess what?
-
- I don't need permission from you to do anything....
- /i/smilies/16x16_smiley-wink.gif -

I understand him. Seafire says his reasons pretty clearly in his post.

Dont even try to behave like you are seeking for balanced game, when you are not. Now when you managed to ruin for example relative performance of B-239 and I-16, why dont you cry out to correct the rest of Brewsters FM, like level speed? It should fly 430km/h at sea level, now I-16 beats Brewster, which really is not historical.

But now Brewster is like you wanted it. Not like it was historically. So end of "testing".

XyZspineZyX
09-08-2003, 10:40 PM
~S~

Well, as a wild guess, could it be the ejector recoil?

When guns fire not only do they recoil back [and up in the case of a rifle] but also away from the direction the case is ejected from.

XyZspineZyX
09-08-2003, 11:01 PM
VOL_jon, you have a point, except that the P-47 weighs in at a heafty 21000lbs (thats over 10 tons) at takeoff. Get that scooting through the air at 350mph, and 8 .50cal shouldn't shake it much at all. Certainly no pronounced yaw movement should be noticed.

It's a bug, no biggie.

XyZspineZyX
09-09-2003, 07:25 AM
It is extremely hard to kill outright in a P-47 esp an FW190 even at sustained fire due to the nose wabdering all over the place and perhaps lack of firepower modelled, but this assertion is difficult to prove. BTW the AI seem to require only a fraction of a second burst to down 109s and not too much longer for a 190.

I just notice I get better hits with lowly P_40 and Hurricane than with the much celebrated 8 50 cals of the P-47. This does not bode well when the player flyable P-51 six guns enter the theatre.

XyZspineZyX
09-09-2003, 04:23 PM
AaronGT wrote:
- I did it in the air. No movement with engine on or
- off thatI could see. There is recoil, but no
- consistent
- yaw that I could discern. I can do a track if you
- like.
-
- I didn't try it on the ground.

Hmmm - on the ground it does produce a definite right inclination, however when flying I get the same kind of result as you (now using v1.11).
Plane wobbles about quite a lot when firing but doesn't veer away from the flight path.
The effect in flight is similar to the recoil in the P-40, though a little larger IMHO.
Mk108s in the 190s wing produce a much greater yaw effect - reasonably enough - but you generally don't need a long burst with them /i/smilies/16x16_robot-happy.gif
In the rare instances when I've been able to get a good concentrated burst on target the 8x.50 battery does the job really well.

Cheers

Athos



"When first under fire and you're wishful to duck, don't look nor take heed at the man that is struck, be thankful you're living, and trust to your luck, and face to your front like a soldier"
ex. Rudyard Kipling